Bicycle Chain, is subject to dirt build up because of its closeness to the ground when in use. Because of its position relative to the wheels, it is subjected to dirt and debris flying upward from the front tire and dirt and debris carried around by the back tire.
The susceptibility of chains to dirt build up and increased friction losses and malfunction caused by dirt build up is especially evident in bicycles used off roads and off paved tracks. Dirt build up induced power reduction and malfunction are especially serious in bicycles used on dirt and sand and particularly racing bicycles used on uneven dirt tracks.
When chains of conventional design are employed, dirt tends to accumulate on a chain and to slow or jam the chain. Dirt particularly accumulates in areas between adjacent pin plates and bushing plates, increasing frictional resistance to their normal pivoting or causing jamming and preventing their pivoting and preventing their fully or correctly engaging spocket teeth. That causes other increased friction loss and slowed bicycle operation or spocket jumping and stopping of a bicycle.
While many chains and many roll-type chains have been used, no chains with substantial spacing between bushing plates and pin plates have been considered as a means of preventing dirt build up in bicycle chain environments.